CCAMLR

This paper presents an analysis of data gained from nine years of tagging of Patagonian toothfish (Dissostichus eleginoides) in Subarea 48.3. In addition to providing information on tagging procedure, Patagonian toothfish biology, growth and local movement of Patagonian toothfish in 48.3 (presented in WG-SAM-14/35), it describes the spatial movements and regional connectivity in Subarea 48.3. The characterisation of tag recapture data from Subarea 48.3 shows that the tagging programme is successful in providing substantial information for the stock assessment and that it can give a first indication of spatial areas of biological interest, such as potential spawning and nursery grounds.

Elasmobranch species, such as skates (Rajiformes), are not target species within the CCAMLR longline fisheries. However, they form a major part of the bycatch and as such it is necessary to understand the effect of each fishery on the Rajiformes population. Here we describe biological information gained from the skate tag-release programme in statistical subarea 48.3 and use the tag recaptures for a simple Petersen model estimation of the population trends. The bycaught Rajiformes in subarea 48.3 are mostly one species, Amblyraja georgiana, and the Petersen estimation indicates that the stock is currently stable and has been since at least 2010.

Data from electronic archival tags are often used to characterise movement and migration patterns in fishes. Understanding these movement patterns is one of the key information needs for the assessment and management of Antarctic toothfish. We deployed 4 pop-off satellite archival tags on large toothfish on the Ross Sea slope in January 2013 and report on the first recovery of an Antarctic toothfish tagged with an archival tag. The fish was recaptured in the fishery the following season (December 24, 2013), providing 335 days of data archived at 10 min intervals. Summaries of raw data show strong and contrasting patterns throughout the time series in several variables recorded and several periods with distinct behavioural profiles, suggesting significant activity throughout the winter period. With the lack of any daylight signal resulting from constant light or darkness, along with living below the photic zone and under ice, positioning using light-based geolocation is not possible. Current efforts focus on developing a Bayesian modelling approach to fit the most likely movements of the tagged fish during its time at liberty, based on the environmental variables recorded by the tag compared with spatial environmental data on depth, temperature and magnetic field strength.

This paper investigates factors affecting the bycatch of skates (Rajiformes) and grenadiers (Macrouridae) taken by the longline fishery in statistical subarea 48.3. Bycatch was greater for vessels using autoline system than for those using the “Spanish” system, due to differences in proximity to the sea bed and type of bait used. The areas of greatest catch rates differed by area and depth range. During the period 1996–1999 skate bycatch was higher in February-March, while that of grenadiers was lower in July-August; since the limitation to a winter longline fishery there in no longer any significant seasonal variation.

Most things related to Dissostichus spp. in the eastern side of Antarctic has not been known well as namely the area is data poor areas. In the Division 58.4.1 there are two stocks; one extends from the SSRU 58.4.1C to the SSRU 58.4.2A, and the other one to the SSRU 58.4.1H. The population sizes were vulnerable with a big range of about 100-1,500 t per SSRU in 58.4.2. During the 2004-2014 fishing seasons in Division 58.4.2, 1,618 Dissostichus spp. were tagged and released, but any tagged fish have not been recaptured. Therefore, there were not enough data to estimate stock biomass for considering the precautionary catch limit. The catch limits agreed during the meetings in 2013 increased to get more recapture. The food-web of Dissostichus spp. has started to be studied in the southern Ross Sea and 58.4.1C. Some studies on biology of the fish have been evaluated, but those are not enough to assess the stocks and consider proper management measures. Based on CCAMLR’s fishery report, the eastern area is still data-poor area showing low recapture rate. Consequently, providing catch and effort data from the area, analysing biological samples, and collecting recapture data focusing on SSRUs in Division 58.4.2 is very important.

Therefore, Korea notifies the participation in exploratory fishery for Dissostichus spp. in the SSRUs in Division 58.4.2 from 2014/2015 season to 2018/2019 using Korean commercial bottom longline vessel, KINGSTAR belonged to Sunwoo Company in accordance with paragraph of CM 24-01 and paragraph 6 (iii) of CM 21-02 to collect the catch and effort, CTD, tagged and released, recaptured data including archival tag, biological data for estimating biomass for Dissostichus spp. using CASAL and evaluating migration and distribution pattern by developmental maturity and size stages.

Most things related to Dissostichus spp. in the eastern side of Antarctic has not been known well as namely the area is data poor areas. In the Division 58.4.1 there are two stocks; one extends from the SSRU 58.4.1C to the SSRU 58.4.2A, and the other one to the SSRU 58.4.1H. The population sizes were vulnerable with a big range of about 1,000-2,000 t per SSRU in 58.4.1. During the 2004-2014 fishing seasons in Division 58.4.1, 4,998 Dissostichus spp. were tagged and released, but only 14 fishes among them have been recaptured which were not enough data to estimate stock biomass for considering the precautionary catch limit. Therefore, the catch limits that the meeting got in 2013 meetings increased to get more recapture. The food-web of Dissostichus spp. has started to be studied in the southern Ross Sea and 58.4.1C. Some studies on biology of the fish have been evaluated, but those are not enough to assess the stocks and consider proper management measures. Based on CCAMLR’s fishery report, the eastern area is still data-poor area showing low recapture rate. Consequently, providing catch and effort data from the area, analysing biological samples, and collecting recapture data focusing on SSRUs in Division 58.4.1 is very important.

The Korean scientists collected and analysed the catch, effort, and biological data such as length, weight, gonadal development, and muscle by NO. 3 INSUNG in Division 58.4.1 during 2012/2013 season. However, the results were still not good enough according to lack of data because of the bad sea-ice condition for the survey. Therefore, we will extend the research area and sample size of catch and fishing efforts, and biological data to get more accuracy and effective results to manage the eastern side area of Antarctic.

Therefore, Korea notifies the participation in exploratory fishery for Dissostichus spp. in the SSRUs in Division 58.4.1 from 2014/2015 season to 2018/2019 using Korean commercial bottom longline vessel, KINGSTAR belonged to Sunwoo Company in accordance with paragraph of CM 24-01 and paragraph 6 (iii) of CM 21-02 to collect the catch and effort, CTD, tagged and released, recaptured data including archival tag, biological data for estimating biomass for Dissostichus spp. using CASAL and evaluating migration and distribution pattern by developmental maturity and size stages.

Most things related to Dissostichus spp. in the eastern side of Antarctic has not been known well as namely the area is data poor areas. In the Division 58.4.1 there are two stocks; one extends from the SSRU 58.4.1C to the SSRU 58.4.2A, and the other one to the SSRU 58.4.1H. The population sizes would be vulnerable like the neighbour divisions if there is the same population. During the 2004-2014 fishing seasons in Subarea 48.6, 3,589 Dissostichus spp. were tagged and released, but only 4 fishes among them have been recaptured which were not enough data to estimate stock biomass for considering the precautionary catch limit. Therefore, the catch limits that the meeting got in 2013 meetings increased to get more recapture. The food-web of Dissostichus spp. has started to be studied in the southern Ross Sea and 58.4.1. Some studies on biology of the fish have been evaluated, but those are not enough to assess the stocks and consider proper management measures. Based on CCAMLR’s fishery report, the eastern area is still data-poor area showing low recapture rate. Consequently, providing catch and effort data from the area, analysing biological samples, and collecting recapture data focusing on SSRUs in Subarea 48.6 is very important.

Therefore, Korea notifies the participation in exploratory fishery for Dissostichus spp. in the SSRUs in Subarea 48.6 from 2014/2015 season to 2018/2019 using Korean commercial bottom longline vessel, KINGSTAR belonged to Sunwoo Company in accordance with paragraph of CM 24-01 and paragraph 6 (iii) of CM 21-02 to collect the catch and effort, CTD, tagged and released, recaptured data including archival tag, biological data for estimating biomass for Dissostichus spp. using CASAL and evaluating migration and distribution pattern by developmental maturity and size stages.
 

An updated and revised assessment of the Patagonian toothfish (Dissostichus eleginoides) stocks in Kerguelen and Crozet areas is presented. This study is based on a CASAL (C++ Algorithmic Stock Assessment Laboratory) model. Different statistical and biological datasets are used: catches, tag releases/recaptures data, commercial catch-at-length data and data from the recent POKER survey (2013). Preliminary results show stable estimates of biomass and SSB never fall below 60% of the initial biomass considering the actual level of catches (5100t in Kerguelen and 700t in Crozet).
 

We addressed the revisions requested by the WG-SAM-14 regarding the results of the second year of Spanish research experience and ongoing research plan presented in WG-SAM- 14/12 and WG-SAM-14/09. 

A summary of the results of the Spanish research that took place in the 58.4.1 division during the last two fishing seasons is presented.   

A prospective estimation of the local biomass (B_LOC) of three SSRUs visited using the local depletion method, together with the extrapolation to the total Biomass in the entire SSRUs, as well as an estimation of the Biomass in SSRU 58.4.1H using the mark-recapture Petersen model is made.